591 results about "Thin-film bulk acoustic resonator" patented technology

A telemetry receiver for an implantable medical device (IMD) such as a cardiac pacemaker has an RF antenna coupled to a telemetry circuit that includes an out-of-band rejection filter comprising a thin film bulk acoustic resonator filter. The telemetry circuit includes an amplifier coupled to the thin film bulk acoustic resonator filter and a demodulator coupled to the amplifier. The filter, amplifier and demodulator are all fabricated on a common integrated circuit die. A multichannel telemetry receiver for an IMD has a plurality of thin film bulk acoustic resonator bandpass filters defining individual channels. Identification of a preferred data transmission channel for communication of programming data to the IMD is determined by obtaining samples of the signals being passed by each of a plurality of thin film bulk acoustic resonator bandpass filters that define individual channels and evaluating the samples to determine the noise level for each channel.

A pit (52) is formed in a substrate comprising a silicon wafer (51) on a surface of which a silicon oxide thin layer (53) is formed. A sandwich structure (60) comprising a piezoelectric layer (62) and lower and upper electrodes (61, 63) joined to both surfaces of the piezoelectric layer is disposed so as to stride over the pit (52). The upper surface of the lower electrode (61) and the lower surface of the piezoelectric layer (62) joined to the upper surface of the lower electrode are treated so that the RMS variation of the height thereof is equal to 25 nm or less. The thickness of the lower electrode (61) is set to 150 nm or less. According to such a structure, there is provided a high-performance thin film bulk acoustic resonator which are excellent in electromechanical coupling coefficient and acoustic quality factor.

The film acoustically-coupled transformer (FACT) has a first and second decoupled stacked bulk acoustic resonators (DSBARs). Each DSBAR has a lower film bulk acoustic resonator (FBAR), an upper FBAR atop the lower FBAR, and an acoustic decoupler between them FBARs. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. A first electrical circuit interconnects the lowers FBAR of the first DSBAR and the second DSBAR. A second electrical circuit interconnects the upper FBARs of the first DSBAR and the second DSBAR. In at least one of the DSBARs, the acoustic decoupler and one electrode of the each of the lower FBAR and the upper FBAR adjacent the acoustic decoupler constitute a parasitic capacitor. The FACT additionally has an inductor electrically connected in parallel with the parasitic capacitor. The inductor increases the common-mode rejection ratio of the FACT.

A method for fabricating a resonator, and in particular, a thin film bulk acoustic resonator (FBAR), and a resonator embodying the method are disclosed. An FBAR is fabricated on a substrate by reducing mass from a top electrode layer. For a substrate having multiple resonators, mass is reduced from only selected resonator to provide resonators having different resonance frequencies on the same substrate.

A thin film bulk acoustic resonator includes a piezoelectric film, and a pair of electrodes between which the piezoelectric film is interposed. The piezoelectric film includes an outer region extending outwards from at least a portion of the periphery of a resonator portion composed of the pair of electrodes and the piezoelectric film. The outer region includes, in at least a portion thereof, an acoustic damping region for damping acoustic waves.

A band-pass filter has a ladder-type circuit including first and second terminals whose characteristic impedances are Z0, and series elements and shunt elements disposed between a first terminal and a second terminal, each of the series elements and shunt elements containing a film bulk acoustic resonator. Assuming that characteristic impedance of any one of the series elements is Z1 and that characteristic impedance of any one of the shunt elements is Z2, the characteristic impedances Z0, Z1, and Z2 have a relation of 1<(Z1 / Z0)<2, preferably 1.3<(Z1 / Z0)<1.7, and 0.5<(Z2 / Z0)<1, preferably 0.6<(Z2 / Z0)<0.8.

Disclosed are a film bulk acoustic resonator, a duplexer filter having the same, and a semiconductor package thereof. The film bulk acoustic resonator comprising: a semiconductor substrate; a lower electrode more than two layers formed at an upper surface of the semiconductor substrate; a piezoelectric layer deposited on an upper surface of the lower electrode with a certain thickness; and an upper electrode more than two layers formed at an upper surface of the piezoelectric layer, has an excellent bonding characteristic. The duplexer filter can microminiaturize a size thereof by integrating a film bulk acoustic filter formed by connecting the plurality of film bulk acoustic resonators serially and in parallel and peripheral passive elements of the film bulk acoustic filter into one semiconductor chip. Also, the semiconductor package is suitable for the duplexer filter.

The invention discloses a thin film bulk acoustic wave resonator which comprises a substrate, a buffer layer, a piezoelectric layer and electrodes, and is characterized in that 1. A smooth concave groove and the buffer layer are arranged on the upper end surface of the substrate; the buffer layer crosses the concave groove and forms an air gap provided with a smooth upper convex edge with the substrate, and completely covers the air gap; the height of the lower top surface of the air gap is less than that of the substrate, and the air gap has flat surface and even change edge; 2. The edge of the buffer layer, which is contacted with the air gap and is close to the substrate is in smooth and outer-convex shape; the piezoelectric layer is arranged on the buffer layer; the electrodes include a bottom electrode and a top electrode; the bottom electrode is arranged in the piezoelectric layer on the buffer layer; the top electrode is arranged on the piezoelectric layer. The thin film bulk acoustic wave resonator has ingenious structure; a FBAR with stable structure and low loss can be fabricated on the substrate through the method, and the CMP process is avoided, so the thin film bulk acoustic wave resonator can be integrated into a CMOS chip conveniently.

The film acoustically-coupled transformer (FACT) has decoupled stacked bulk acoustic resonators (DSBARs), a first electrical circuit and a second electrical circuit. Each of the DSBARs has a lower film bulk acoustic resonator (FBAR), an upper FBAR and an acoustic decoupler. The upper FBAR is stacked on the lower FBAR and the acoustic decoupler is located between the FBARs. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. The first electrical circuit interconnects the lower FBARs. The second electrical circuit interconnects the upper FBARs. The FBARs of one of the DSBARs differ in electrical impedance from the FBARs of another of the DSBARs. The FACT has an impedance transformation ratio greater than 1:m2, where m is the number of DSBARs. The actual impedance transformation ratio depends on the ratio of the impedances of the FBARs.

Embodiments of an acoustically-coupled transformer have a first stacked bulk acoustic resonator (SBAR) and a second SBAR. Each of the SBARs has a lower film bulk acoustic resonator (FBAR) and an upper FBAR, and an acoustic decoupler between the FBARs. The upper FBAR is stacked atop the lower FBAR. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. The piezoelectric element is characterized by a c-axis. The c-axes of the piezoelectric elements of the lower FBARs are opposite in direction, and the c-axes of the piezoelectric elements of the upper FBARs are opposite in direction. The transformer additionally has a first electrical circuit connecting the lower FBAR of the first SBAR to the lower FBAR of the second SBAR, and a second electrical circuit connecting the upper FBAR of the first SBAR to the upper FBARs of the second SBAR.

An apparatus having a thin film bulk acoustic resonator (FBAR) with positively sloped bottom electrode and a method of making the same is disclosed. The resonator has a bottom electrode, a top electrode, and core material. The bottom electrode includes a positively sloped edge. To make the apparatus including the resonator, first, a bottom electrode layer is deposited. Then, the bottom electrode layer is dry etched to fabricate a bottom electrode having a positively sloped edge. Next, a core layer is fabricated above the bottom electrode. Finally, a top electrode is fabricated over the core layer.

Disclosed are a film bulk acoustic resonator (FBAR) device and a method for fabricating the film bulk acoustic resonator (FBAR) device. The film bulk acoustic resonator (FBAR) device comprises a membrane layer having a plurality of active regions and provides different resonant frequencies by providing different thicknesses of the active regions of series resonators and shunt resonators, and by controlling the thicknesses, respectively. A plurality of the film bulk acoustic resonator (FBAR) devices having different resonant frequencies are manufactured on a substrate, thereby simultaneously manufacturing a transmission filter and a reception filter on the same substrate. Further, the film bulk acoustic resonator (FBAR) device has a stable structure and excellent characteristics.

A thin film bulk acoustic resonator comprises a substrate (12) of a silicon single crystal, a base film (13) formed on the substrate (12) and composed of a dielectric film mainly containing silicon oxide, and a piezoelectric stacked structure (14) formed on the base film (13). A vibratory section (21) composed of a part of the base film (13) and a part of the piezoelectric stacked structure (14). The piezoelectric stacked structure (14) includes a lower electrode (15), a piezoelectric film (16), and an upper electrode (17) formed in this order from below. The substrate (12) had a via hole (20) in the region corresponding to the vibratory section (21). The via hole forms a space for allowing vibration of the vibratory section (21). The piezoelectric film (16) is an aluminum nitride thin film containing 0.2 to 3.0 atom % of alkaline earth metal and / or a rare earth metal. Thus, the thin film bulk acoustic resonator has a high performance such as a large electromechanical coupling coefficient, an excellent acoustic quality factor (Q) and an excellent frequency-temperature characteristic.

Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate having parallel front and back surfaces, the back surface attached to the substrate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate such that interleaved fingers of the IDT are disposed on a portion of the piezoelectric plate suspended over a cavity formed in the substrate.

A method for fabricating a film bulk acoustic resonator (FBAR) includes depositing a dielectric layer on a substrate, providing a sacrificial layer on part of the dielectric layer; providing a bottom electrode on part of the sacrificial layer on part of the dielectric layer; providing a piezoelectric layer on the bottom electrode; patterning a top electrode on the piezoelectric layer; and removing the sacrificial layer. The substrate may have a cavity receiving the sacrificial layer. As a result, a cantilevered resonator having an air gap between the bottom electrode and the dielectric layer may be simply fabricated.

A duplexer includes: first and second filters including film bulk acoustic resonators (FBARs) arranged in a ladder form; first and second integrated-passive devices (IPDs) provided between a common terminal and the first and second filters; and a substrate on which the first and second filters and the first and second IPDs are mounted. The substrate includes conductive patterns that realize inductances connected between the first and second filters and ground. The first and second IPDs includes inductors connected to the first and second filters.

A film bulk acoustic resonator includes: a substrate having; a lower electrode extending; a piezoelectric film provided on the lower electrode; an upper electrode opposed to the lower electrode and provided on the piezoelectric film; and a plurality of protrusions. The substrate has a cavity in a surface thereof. The lower electrode extends above the cavity from an upper surface of the substrate. The protrusions are provided below the lower electrode in the cavity.

A tuning circuit for adjusting an oscillation frequency of an oscillator circuit. The tuning circuit comprises a film bulk acoustic wave resonator (FBAR) having a series resonance frequency and a parallel resonance frequency, and an inductor coupled in series or parallel with the film bulk acoustic wave resonator. The series connection of the inductor and FBAR decreases the series resonance frequency. The parallel connection of the inductor and the FBAR increases the parallel resonance frequency. The tuning circuit further comprises a varactor coupled in series or parallel with the inductor and the FBAR combination. The varactor tunes the oscillation frequency over the increased tuning range.

Resonator devices, filter devices, and methods of fabrication are disclosed. A resonator device includes a substrate and a single-crystal piezoelectric plate having parallel front and back surfaces. An acoustic Bragg reflector is sandwiched between a surface of the substrate and the back surface of the single-crystal piezoelectric plate. An interdigital transducer (IDT) is formed on the front surface. The IDT is configured to excite shear acoustic waves in the piezoelectric plate in response to a radio frequency signal applied to the IDT.

A thin film bulk acoustic resonator is provided in which the spurious caused by a lateral vibration mode is reduced. The thin film bulk acoustic resonator includes a laminated body having a first electrode 12, a piezoelectric layer 13 adjacently formed on an upper surface of the first electrode 12, and a second electrode 14 adjacently formed on an upper surface of the piezoelectric layer 13, and is made such that these first and second electrodes 12 and 14 have boundary surfaces contacting with air, in which the whole end surface of the piezoelectric layer 13 is made to exist inside the first electrode 12 and second electrode 14.

The film bulk acoustic wave resonator includes a laminate structure composed of a piezoelectric layer, and first and second electrode layers interposing at least part of the piezoelectric layer, in which the first metal electrode is dispersively formed on an electrode plane facing the second metal electrode, and a gap is formed in a substrate correspondingly to the laminate-structured resonance part. Except for an area of a wire electrode electrically connected to the first electrode layer and an area of a wire electrode electrically connected to the second electrode layer, the piezoelectric layer, first electrode layer and second electrode layer do not come in contact with the insulating substrate but are supported on a hollow. Also, a prop is formed in the gap to support the laminate structure.

A tuneable film bulk acoustic resonator (FBAR) device. The FBAR device includes a bottom electrode, a top electrode and a piezoelectric layer in between the bottom electrode and the top electrode. The piezoelectric layer has a first overlap with the bottom electrode, where the first overlap is defined by a projection of the piezoelectric layer onto the bottom electrode in a direction substantially perpendicular to a plane of the bottom electrode. The FBAR device also includes a first dielectric layer in between the piezoelectric layer and the bottom electrode and a mechanism for reversibly varying an internal impedance of the device, so as to tune a resonant frequency of the FBAR device.

There is disclosed acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The interleaved fingers of the IDT are substantially molybdenum. The piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a primary shear acoustic mode in the diaphragm. A thickness of the interleaved fingers of the IDT is between 0.25 times and 2.5 times a thickness of the piezoelectric plate.